无法让 ImageResizer 调整我的 Pdf 大小

Question

我刚刚开始使用 ImageResizer 为我的图像创建缩略图，使用下面他们网站上的代码。

private void CreateThumbnail()
{
    Dictionary<string, string> versions = new Dictionary<string, string>();
    //Define the versions to generate
    versions.Add("_thumb", "width=100&height=100&crop=auto&format=jpg"); //Crop to square thumbnail
    versions.Add("_medium", "maxwidth=100&maxheight=100&format=jpg"); //Fit inside 400x400 area, jpeg
    versions.Add("_large", "maxwidth=1900&maxheight=1900&format=jpg"); //Fit inside 1900x1200 area

    //Loop through each uploaded file
    foreach (string fileKey in HttpContext.Current.Request.Files.Keys)
    {
        HttpPostedFile file = HttpContext.Current.Request.Files[fileKey];
        if (file.ContentLength <= 0) continue; //Skip unused file controls.

        //Get the physical path for the uploads folder and make sure it exists
        string uploadFolder = MapPath("~/Images");
        if (!Directory.Exists(uploadFolder)) Directory.CreateDirectory(uploadFolder);

        //Generate each version
        foreach (string suffix in versions.Keys)
        {
            //Generate a filename (GUIDs are best).
            string fileName = Path.Combine(uploadFolder, "AssetID" + suffix);

            //Let the image builder add the correct extension based on the output file type
            fileName = ImageBuilder.Current.Build(file, fileName, new ResizeSettings(versions[suffix]), false, true);                
        }
    }
}

但是，当我将此代码应用于 Pdf 时，它崩溃并出现错误 'File may be corrupted, empty, or may contain a PNG image with a single dimension greater than 65,535 pixels.' 我需要进行哪些更改才能调整 Pdf 的大小？我已经阅读了他们的文档，虽然它似乎会从 Pdf 创建缩略图，但示例都使用图像。

这是包含 PdfRenderer 的插件列表

Answer 1

未安装 PdfiumRenderer 或 PdfRenderer 插件（无论您选择哪个）。因此，主解码器无法解码图像。

您必须安装 PDF 插件才能使用。

PdfiumRenderer 是两者中较好的。

见http://imageresizing.net/docs/v4/plugins/pdfiumrenderer

无法让 ImageResizer 调整我的 Pdf 大小

Cannot get ImageResizer to resize my Pdf

c#

pdf

thumbnails

imageresizer